preheat work - part 1

src/libslic3r/GCode.cpp

@@ -1527,6 +1527,7 @@ void GCode::do_export(Print* print, const char* path, GCodeProcessorResult* resu
     path_tmp += ".tmp";
 
     m_processor.initialize(path_tmp);
+    m_processor.set_print(print);
     GCodeOutputStream file(boost::nowide::fopen(path_tmp.c_str(), "wb"), m_processor);
     if (! file.is_open()) {
         BOOST_LOG_TRIVIAL(error) << std::string("G-code export to ") + path + " failed.\nCannot open the file for writing.\n" << std::endl;